Inclosed concentric recoil mechanism to facilitate replacement of gun tubes



KRAMER ETAL INCLOSED CONCENTRIC RECOIL MECHANISM TO FACILITATE REPLACEMENT OF GUN TUBES Filed May l1, 1951 Aug. 23, 1955 ENCLOSED CONCENTRIC RECOIL MECHANISM T FACILITATE REPLACEMENT 0F GUN TUBES Alexander E. Kramer, Hyattsville, Md., and Herman A. Matson, Washington, D. C., assignors to the United States of America as represented by the Secretary of the Army Claims.

The invention described in the specication and claims may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to hydraulic recoil mechanisms for guns and more particularly to hydraulic recoil mechanisrns adapted to facilitate replacement 0f the gun barrels.

A major problem arising in connection with guns mounted in vehicles such as tanks is replacement of worn barrels. Such replacement has heretofore been quite difficult, usually necessitating removal of the breech ring, breech block or some other part of the weapon. In addition, the hydraulic recoil iiuid frequently leaks out during the replacement operation, requiring that the recoil chamber be refilled. lt is accordingly a primary object of our invention to provide a gun in which barrels can be interchanged without removal of any other part of the weapon. A second object oi our invention is provision of a gun with a hydraulic recoil system from which the barrel can be removed without loss of hydraulic fluid. Other objects of the invention will be evident hereinafter.

We have found that the objects of our invention can be achieved by providing a unitary self-contained recoil system, concentric or coaxial with the gun barrel, used in conjunction with simple fastening means for attaching the barrel to the breech-ring. How these objects are achieved can be seen by reference to the following description and accompanying drawings in which:

Figure l represents a longitudinal view of our invention partly in section;

Figure 2 shows an enlarged View of the forward portion only of Figure l with some detail of the seating ring; and

Figure 3 shows an enlarged cross-sectional View of the seating ring.

In the figures a gun barrel 1@ is shown held by interrupted threads 11 at its breech end fitting into corresponding threads 12 in the breech ring 13. This breech ring is conventional and associated with other conventional elements such as extractor 14, breech-block oprerating crank 15 and crank-shaft 16. Extending through the breech ring to the sectored receiving threads in oil port 17.

Held by threads 13 to the breech ring is sleeve 19 coaxial with and slidably litting the gun barrel 10. A rear ring and a forward ring 21 have a sliding fit on sleeve 19 and, when the gun is in battery position, are located near the breech and muzzle ends of the sleeve respectively. A housing 22 is carried by rings 20 and 21, being fastened to ring 21 by threads 25 and to ring 2Q through threads 23 on ring 24, the latter ring tightly encircling ring 20. Bracket 26 is rmly mounted on housing 22 as a support for the gun, holes 27 being provided for the bolts required to hold the gun in its cradle. Stops 28 are mounted externally in ring 2i) next the ttes Patent' breech ring and contact the forward face thereof to limit rearward movement of the ring upon sleeve 19.

Sleeve 19 and housing 22, coaxial therewith, have between them a space 29 closed at one end by ring 20 and at the other end by ring 21. A third ring, seating ring 30, divides this enclosed space 29 into two chambers, a rear recoil chamber 31 and a front first counterrecoil chamber 32. Within recoil chamber 31 is recuperator spring 33 loosely surrounding sleeve 19, and abutting backing plate 34 at its breechward end and seating ring 30 at its forward end. The enclosed space 29 is normally lled with oil or other viscous fluid to oppose recoil and counter-recoil, the fluid becoming pressurized during each operation. Ports 35 are provided through the housing 22 into space 29 for supply and drainage. Packings 36, 37, 38, 39, 40, 41 and 42 aid in retaining oil in the two chambers.

Seating ring 30 consists of a cylindrical body 43, made-up of a group of distinct lingers 44, and a web i5 upon which the recuperator spring 33 is actually seated and to which the iingers 44 are connected. This ring is coaxial with sleeve 19 and held thereon for recoil as a unit with the sleeve by iiange 46 and weld 47. Other retaining means may be employed as desired.

It is clear from Figures l and 2 that housing 22 includes a ared portion 54 extending progressively outwardly and forwardly from a transverse plane indicated at i8 to its muzzle end. When the parts are in battery position ring 313 is at or near the forward end of housing 22 and, in this position, has a relatively loose fit therewithin so that cil may iiow between the ring and the housing with a minimum of obstruction. r.The annular space between the ring and the housing forms a passageway i9 between the recoil and first counter-recoil chambers through which oil can iiow from one chamber to the other. As ring 30 moves rearwardly in the housing 22 with the recoil of the gun, the clearance between the ring and the housing becomes less until, when the ring passes plane 48, it has decreased to a comparatively snug tit in the rear cylindrical part of the housing. A plurality of circumferentially-spaced slots or oriiices Si? are milled in ring 39 to permit a restricted or limited passage of iiuid between the ring and housing 22 during the initial portion of the recoil movement. These slots appear in Figure 2 as channels between the fingers 44 of the seating ring. This channel construction permits the resistance to recoil created by the flow of fiuid from chamber 31 to chamber 32 to increase progressively with the distance or amount of recoil movement.

The action of seating ring 3i) is essentially that of a buier against the recoil of the gun. ln somewhat similar fashion frontward ring 21 acts as a buffer on the counterrecoil action of the gun. The rear part of ring 21 flares outwardly into a cylindrical projection 51. Between projection 51 and sleeve 19 is a second and smaller counter-recoil chamber 52. Sleeve 19 has a ver] slight inward taper before the plane indicated at S3. As long as the gun is in battery position, the projection 51 on ring 21 just makes contact with sleeve 19 and completely closes chamber 52. When the gun goes into recoil carrying sleeve 19 with it the taper on the sleeve causes a clearance to appear between the sleeve and the projection, opening chamber S2 into chamber 32. Oil is now free to iiow between these two chambers. When counter-recoil occurs, oil is forced under increasing pressure into the chamber 52 building up a back pressure against the counter-recoil. The passageway between the first and second counter-recoil chambers is closed upon the completion of the counter-recoil action, pinching off a small quantity of oil in the second chamber. The throttling of the oil between the sleeve and the projection 51 is similar to that occurring between the taper of the housing 22 and web 45.

The functioning of our recoil mechanism is clear from the foregoing description. When the gun is fired the barrel 10, breech ring 13 and sleeve 19 recoil as a unit relatively to housing 22. The resistance of the recuperator spring and the resistance to flow of the oil about and through ring 21 absorb the forces of recoil. The constricted design of the housing plus the dual nature of the orifices is adopted to ensure the force opposing recoil approaches a maximum rapidly after the beginning of the recoil movement and then maintains the maximum for the remainder of the movement. The counter-recoil force is opposed by the pressurization of the oil in the counter-recoil chambers and is reduced to a minimum thereby.

It will be seen that our concentric recoil system is entirely self-contained and that the gun barrel can easily be slipped through the inner sleeve for insertion or removal without loss of oil. Furthermore a change in barrels can be effected without disassembly of any parts of the weapon other than the barrel itself. lt is thus no longer necessary to take a tank armed with a 75 or 105 mm. gun,- for example, to a third echelon ordnance repair shop merely for replacement of the gun barrel. Consequently the objects of our invention are achieved in a relatively simple and inexpensive manner.

What we claim is:

l. An inclosed unitary recoil mechanism to facilitate replacement of gun barrels from the forward end of a gun comprisingr a cylindrical housing, a cylindrical sleeve,

mounted coaxially within the housing, fluid tight rings fastened rigidly to the housing and making sliding Contact with the sleeve, recoil and counter-recoil chambers formed between the housing and the sleeve, a mass of viscous fluid in said chambers, a passageway connecting the two chambers, resilient means in the recoil chamber interconnecting the housing and the sleeve, a breech ring having a female portion adapted to receive and secure the breech end of a gun barrel, said sleeve having an internal diameter larger than said female member to allow insertion of a gun barrel from the front of said mechanism and means for securing the sleeve to the breech ring of the gun.

2. ln combination, a breech ring, a gun barrel removably threaded to said breech ring, and an inclosed unitary recoil mechanism to facilitate replacement of said gun barrel likewise threaded to the breech ring, said recoil mechanism comprising a sleeve coaxial with and fitting about the gun barrel and secured to the breech ring only, a cylindrical housing coaxially positioned about the sleeve in radially spaced relation therewith, fluid tight rings secured to and closing the respective ends of the housing and making fluid-tight sliding contact with said sleeve, said rings defining an inclosed cylindrical space between the housing and the sleeve, a seating ring secured to the sleeve within said space and dividing the same into a relatively long rear recoil cham- Cil ber and a relatively short front counter-recoil chamber when the gun is in battery position, said ring having a transverse passage providing communication between said chambers, a recuperator spring in said annular space abutting said seating ring and the rear fluid tight ring at its respective ends to resist recoil of said barrel, said passage in said ring terminating inside the proximate end of said spring so that collapse of the spring during recoil cannot close said passage, and a body of viscous fluid filling said annular space.

3. In combination, a breech ring, a gun barrel threaded to said breech ring and an inclosed unitary recoil mechanism to facilitate replacement of the gun barrel likewise threaded to the breech ring, said recoil mechanism comp'rising a sleeve coaxial with and fitting about the gun barrel and secured to the breech ring only, the breech end of said barrel being smaller than the bore of said sleeve so that the barrel can be inserted and removed from the forward end of said mechanism a cylindrical housing coaxially positioned about and in radially spaced relation with the .sleeve, uid tight rings secured to and closing the respective ends of the housing and making fluid-tight sliding contact with the sleeve, an inclosed annular space between the housing and the sleeve dened by the fluid-tight rings, a mass of fluid in the annular space, a seating ring secured to the sleeve within said space and dividing the same into a relatively long rear recoil chamber and a relatively short front rst counterrecoil chamber when the gun is in battery position, a recuperator spring in said annular space abutting the seating ring and rear uid tight ring at its respective ends to resist recoil of the barrel, a clearance between the seating ring and the housing to provide a passageway for tluid between the recoil and counter-recoil chambers, and a passage extending through said seating ring and terminating inside the proximate end of said spring so that collapse of said spring during recoil cannot close said passage through the ring.

4. The combination of claim 3 further comprising a second counter-recoil chamber formed by a cylindrical projection on the inner surface of the uid tight ring nearest the muzzle of the barrel and the surface of the sleeve.

5. The combination of claim 3 in which a throttling action of the fluid on counter-recoil is provided by a taper on the external surface of the sleeve, said taper being of such dimensions as to close completely the second counter-recoil chamber when the combination is in battery position and to provide a gradually increasing clearance and uid passageway between the first and second counterrecoil chambers during recoil.

References Cited in the file of this patent UNITED STATES PATENTS 2,358,340 Lucht Sept. 19, 1944 2,395,488 Lucht Feb. 26, 1946 2,442,371 Meyers et al June l, 1948 2,454,818 Lucht Nov. 30, 1948 

